This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Our goal is to determine intermolecular interactions that regulate the concerted assembly of Venezuelan equine encephalitis virus (VEEV), an alphavirus that causes epidemics in Central and South America, and a highly developed biological weapons agent without effective therapy. Aim 1. To determine interactions between the VEE virus capsid protein and RNA that promote viral nucleocapsid assembly, using complementary biochemical, biophysical, molecular and structural biology approaches. Aim 2. To determine if intermolecular capsid protein interactions within the nucleocapsid undergo large-scale rearrangements during VEE virus maturation by determining the structure of pre-viral, viral, and post-viral nucleocapsids.